[nsp] SAA RTR and Track Commands

[Cho, David]

Hi All,

I am exploring the option to use SAA command set on 2621 routers but it
seems unsupported at least the track portion of it.  I've checked the CCO
but there was no 12.3(4)T image(required according to DOC) available for
Cisco 2621.  What would you suggest to redistribute static routes to two
different routers which runs ospf on one interface and static on the other?
If SAA works on this case, it would have been the best way to do it.
Obviously, I'd want to avoid the black hole here.  Please see below.


     OSPF  - R1 - Static to WAN site ------
                                          |
                                          |--- HSRP ---- R3 
                                          |
     OSPF  - R2 - Static to WAN site ------

R1 is the primary and R2 is the back up.  If the Ethernet interface of R1 to
R3 fails, I want static redistribution to R1 to stop but R2 static
redistribution takes over.  I've set the metric on R1 and R2 so that R1's
redistributed static route has the preference over R2.


Sample Configuration:
Initial configuration of Customer Router1:
interface Serial0/1
ip address 192.168.2.1 255.255.255.252
interface Ethernet2/2
ip address 192.168.1.1 255.255.255.128
standby ip 192.168.1.3
router bgp 65501
redistribute static
-> advertise static routes via BGP neighbor 192.168.2.2 remote-as 65500
ip route 192.168.1.0 255.255.255.0 Null0
-> static route for the whole class C -- more specific route will be used to
forward packets.
Now, modify the config to only advertise 192.168.1.0/24 via BGP if the
server
(192.168.1.4) is reachable by this router.
Step 1: Configure an SAA probe to ping the server.
rtr 1
type echo protocol ipIcmpEcho 192.168.1.4
rtr schedule 1 life forever start-time now
Step 2: Create a tracked object and associate the object with the SAA probe
that was
previously configured.
track 123 rtr 1 reachability
Step 3: Remove the existing static route.
no ip route 192.168.1.0 255.255.255.0 Null0
Then configure a static route for the prefix to be advertised via BGP, and
associate the
route with the tracked object.
ip route 192.168.1.0 255.255.255.0 Null0 track 123
The above changes remove the static route when the server is not reachable.
This
guarantees that 192.168.1.0/24 will only be advertised via BGP if the server
is reachable
from this router, thus preventing black-holing of packets.